I'm not surprised at all. The character of Quinn was all over the place. There was never a clear vision or path for him.

BF was brought back, I think, as a hedge against James Scott leaving. The talks regarding James' contract broke down and it looked grim. The show still needed a man in that age group and one that could possibly be a villain. But James re-signed and Quinn became superfluous. BF was not disliked but the character was not setting the world on fire. He was an easy one to eliminate and pare down the bloated cast just a bit.